Polyketone Support Structure for PCD Leaching Corrosion
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Solution Overview
Problem
Conventional support structures for PCD material during leaching processes disintegrate when exposed to corrosive leaching mixtures, posing health and safety risks and requiring frequent replacement, while existing leaching techniques use toxic substances that necessitate controlled handling.
Innovation Solution
A support structure formed or coated with polyketone-based plastics, such as PEEK, that protects the PCD element during leaching and withstands the leaching mixture, allowing for the removal of catalyst/solvent and metal carbides using a diluted nitric acid and mineral acid solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional support structures (PTFE, polypropylene, stainless steel) are used during leaching, then the support structure provides initial support for the PCD element, but the support structure disintegrates when exposed to corrosive leaching mixtures, posing health and safety risks and requiring frequent replacement
Solution Approach 1:
The patent applies parameter changes by selecting a plastic material with specific chemical resistance properties that can withstand the corrosive leaching mixture. The support structure is made from plastics such as polyketone, PEEK, PP, or PE, which have been chosen for their ability to resist corrosion from nitric acid and other leaching agents, thereby maintaining structural integrity throughout the leaching process without disintegration.
Solution Approach 2:
The patent employs composite material solutions by using plastic materials that combine chemical resistance with mechanical strength. These plastic support structures represent a composite approach that integrates multiple desirable properties: corrosion resistance from the plastic chemistry, structural integrity for supporting PCD elements, and safety against disintegration, thereby resolving the contradiction between providing support and avoiding harmful disintegration.
2Productivity
If conventional leaching mixtures (aqua regia, hydrofluoric acid) are used to remove catalyst/solvent, then the leaching process effectively removes metallic-solvent/catalysts from PCD material, but the mixtures are highly toxic and corrosive, requiring specialized personnel and well-controlled conditions
Solution Approach 1:
The patent applies parameter changes by substituting the chemical composition of the leaching mixture. Instead of using highly toxic aqua regia or hydrofluoric acid, the patent employs diluted nitric acid (2-5 wt%) combined with mineral acids. This chemical parameter change maintains leaching effectiveness for removing catalyst and solvent from PCD material while dramatically reducing toxicity and safety risks, eliminating the need for specialized personnel and extreme control measures.
3Productivity
If support structures are frequently replaced due to disintegration, then the leaching process can continue, but the process requires frequent interruptions and increases operational complexity
Solution Approach 1:
The patent applies the principle of using disposable support structures made from chemically resistant plastics. These support structures are designed to be inexpensive and replaceable, but more importantly, they are now chemically resistant enough to last through multiple leaching cycles without disintegrating. This eliminates the need for frequent replacements, allowing continuous operation and reducing operational complexity while maintaining the economic advantage of using simple, replaceable components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polyketone-based support structure prevents disintegration and allows for efficient leaching of PCD materials, reducing health risks and the need for frequent replacements, while the nitric acid mixture effectively removes catalysts and carbides, enhancing the thermal stability and performance of PCD materials.
Implementation Method 1
a support structure for a PCD element comprising a support into which a PCD element is locatable; and a sealing element for location in the support structure and configured to protect a non-leached portion of a PCD element during a leaching process, said support being formed from or coated with a polyketone based plastics material
Implementation Method 2
leaching an amount of the diamond catalyst/solvent and/or one or more metal carbides from the PCD material by exposing at least a portion of the PCD material to the leaching mixture
Data Source
AI summary
A support structure (40) for a PCD element (10) comprises a support (42) into which a PCD element (10) is locatable and a sealing element (48) for location in the support structure (40) and configured to protect a non-leached portion of a PCD element (10) during a leaching process. The support (42) is formed from or coated with a polyketone based plastics material.